If you’re like most parents, you’re proudly documenting your child’s firsts: smile, steps, words. But today’s photo albums are filling up with other firsts as well: electronic toy, iPod, computer. These are digital milestones, but you won’t find them in the parenting book on your nightstand.

“There's really is no ‘right’ age to allow our kids to dip a toe into the digital pond,” says the American Academy of Pediatrics’s (AAP) tech expert, Gwenn Schurgin O’Keeffe M.D., author of CyberSafe. “But if we pay attention, we can decide what makes the most sense for our kids, because the reality is these new milestones are coming whether we like it or not.” This certainly isn’t the technology we grew up with. (You probably begged your parents for a bigger television or your own phone—we’re guessing a plastic hamburger or a set of red lips.) Whereas technology once lived in our world, we now live in a world of technology. The Kaiser Family Foundation found that roughly a quarter of all children between the ages of 4 and 6 were using personal computers at least 50 minutes a day—and that study came out four years ago (aka pre-Angry Birds)! “Children today are surrounded by digital media,” says Lori Takeuchi, director of research at the Joan Ganz Cooney Center at Sesame Workshop, a research center in New York City dedicated to “advancing children’s learning in the digital age.” “We found that households with kids ages four to fourteen own, on average, eleven consumer- electronics devices.”

Although the media spends a lot of ink (er, pixels) on the scary aspects (cyberbullying! sexting!), there’s also a great deal of benefi t that kids can reap. “The ability to use technology to seek answers to questions and reach out across the world opens the mind to an almost endless expanse of knowledge,” says Tammi Williams, M.D., a pediatrician at Baylor Medical Center, in Irving, TX. Obviously, children develop at different rates and will be mature enough to handle devices at different ages. The 411 that follows will help you be better prepared whenever your kid takes the technology plunge.

0 TO 12 MONTHS: The Button Pusher

1. Learns cause and effect with electronic toys

2. Handles iPhone set to “airplane mode”

3. Should not hold mobile phone while babbling to Grandma

Every baby toy on the shelves seems to light up and play music. Harvey Karp, M.D., famed Los Angeles-based pediatrician and author of the best-selling book The Happiest Baby on the Block, considers today’s electronic toys to be “modern-day rattles” because they teach cause and effect and also hone manipulative hand skills. But everything in your child’s toy box shouldn’t require double-A batteries. If your child is 9 months or older, make sure you have as many “active” toys as “passive” ones. With passive toys, your child can press a button for the “Mary Had a Little Lamb” light show . Active toys (blocks, balls, etc.) require interaction and participation, and foster fine motor skills.

There is no conclusive evidence about the impact of cellphone use on small children. But cell phones do emit electromagnetic fields, and children’s still-developing skulls are thinner than adults’. If you’re going to call Grandma, have your baby babble on speakerphone or into a headset. If you hand her your phone as a quick distraction, put it on airplane mode, which disables the wireless signal.

We know, we know: The AAP says no television for children under 2, and to limit it to two hours a day for children over 2. But the reality is you just got home from the market, your toddler is fussy and fidgety, and 30 minutes of Bubble Guppies will buy you enough time to put the groceries away and get dinner started.

Luckily, TV can be more than just a high-tech pacifier. A 2005 Kaiser Family Foundation study found that viewing educational programs like Dora the Explorer, Blue’s Clues, and Arthur between the ages of 6 and 30 months was associated with accelerated language growth. However, general television viewing (including exposure to adult programs) was associated with reduced vocabulary. The takeaway: Limited exposure to educational television may have a positive impact on your child, but a household where the boob tube is blaring all day will not. Says Dr. Karp: “It’s not OK to plunk your kid in front of the TV for two hours and think that you’re building his brain, but it is OK if your eighteen-month-old watches Sesame Street.”

Sarah Crisp says her 18-month-old daughter is getting a lot out of Super Why! and WordWorld on PBS Kids. “She knows the ABC song, can recognize lowercase letters, and knows how a letter sounds,” she says. “I don’t think TV is bad. You just have to monitor the amount of time and what they watch.”

One of the big social milestones for toddlers is imitating the behavior of others, so expect your tot to gravitate toward the devices Mommy’s always futzing with. If he’s pining for your phone, let him tinker with a silly app instead of reconfiguring your address book. Try Bubble Popper (free; itunes.com), a causeand- eff ect game that mimics bubble wrap . Again, keep the device on airplane mode— it prevents exposure to unnecessary radiation and reduces any chance of clicking through to the Internet. If you’d prefer that he didn’t play with your iPhone, get him an Alphaberry. It has all the sensory stimulation of Dad’s BlackBerry without the cluttered inbox ($20; onestep ahead.com).

Surprise—eReaders are not solely for adults! There are more than 3,500 children’s books for kids ages 0 to 8 available for the Amazon Kindle, and many eReader titles expand on the basic book interface with “read-to-me” features and a touchscreen.

“At bedtime, the question isn’t what books should we read, it’s ‘Should we read an electronic book or a paper book?’ ” says Nina Lindsey, mom of a 3-year-old daughter and a Nook owner. “She switches between the two, so it’s a good balance.”

You can also try an eReader that doesn’t require supervision, such as the LeapFrog Tag Junior Book Pal ($30; leapfrog .com). Touch the little LeapFrog character to the pages on the board book, and it reads aloud and sounds out letters and words.

Sorting shapes and colors and finding hidden objects are two of the big cognitive milestones for this age group. Fulfi ll her curiosity with Tozzle, an app featuring shape puzzles ($2; itunes.com).

3 TO 4 YEARS: The Swiper

1. Regularly uses a tablet— yours or her own

2. Plays apps that feature simple puzzles and matching games

The iPad is a great platform for handeye coordination, a skill that will serve your child well later, from writing legibly in school to playing sports. Not to mention that in the modern era of technology, we’ve evolved from type to touch to swipe. Thanks to her growing mastery of fi ne motor skills, she’ll be a natural cruising through the tablet’s touchscreen.

But according to Dr. Karp, it’s the variety of apps that makes the iPad such a valuable alternative to other media. “Apps provide a far more beneficial level of engagement than TV ,” he explains. “The interactive experience engages the child much more so than when she’s just absorbing TV images. From a developmental point of view, interactive entertainment is a better option.”

Of course, the iPad features a lot of perks kids don’t need (e-mail, Internet, instant messaging), so it was only a matter of time before they got their own. VTech’s new InnoTab ($80; vtechkids.com) has all the just-like-Mom’s functionality (touchscreen, music and video player, 64 MB of memory), but it’s tooled for tots (e-book reader, art studio, and educational games).

4 TO 5 YEARS: The World Wide Wanderer

1. Uses the Internet under supervision

2. Plays active video games with the family

3. Time to create a new definition of “screen time”

Besides all the giggles sites like Nick Jr. and PBS Kids Sprout can provide, exposure to computers is important for preschoolers because they’re playing an increasingly prominent role in education. (When it comes to apples in the classroom, the iMac has replaced the Granny Smith .)

The key here is supervision. Whether it’s playing Jake’s Jungle Groove on the Disney Junior website or watching that amazing octopus video on YouTube (search “invisible octopus”), do it together. Forget about tracking software: You are the most effective monitoring device.

A few new physical milestones (mastery of running and kicking, and bending over without falling) combined with the social ability to take turns means he’s ready for active video games on the Wii or Xbox 360. But video games should be a family bonding experience. Forty-five percent of moms report that they play games together as a family on a videogame console, according to a recent Parenting-BlogHer survey. So treat it as a family activity.

Some of the best all-ages games on the Wii are Just Dance Kids and Epic Mickey (splash color on a monochromatic landscape to bring it to life). If you’re not sure about a game’s content, use the Entertainment Software Rating Board app (free; itunes.com). Snap a photo of the game box or enter the game’s title, and you’ll score all the information you need. Keep in mind that your child’s exposure to the digital world compounds as he gets older, so count time spent on all devices toward his daily allotted screen time.